Organotypic nervous system tissue culture preparations of spinal cord and dorsal root ganglia are observed with Nomarski differential interference contrast microscopy and time lapse photography. Movements of organelles and particles within growing neurites of such cultures are recorded, and analyzed with the aid of a sonic digitizer, and analyzing motion picture projector in conjunction with an on-line computer system. Particulate motions are examined in growing and maturing culture systems and are compared with alterations in particle and organelle movement in cultures subjected to environmental changes and pharmacologically active agents known to interfere with axoplasmic transport. When human brain biopsy material becomes available for study by similar methods it is hoped that a disorder of particulate axoplasmic flow might be demonstrated in cases of pre-senile dementia and Alzheimer's disease. BIBLIOGRAPHIC REFERENCE: In press--Leestma, J.E.; Velocity Measurement of Particulate Neuroplasmic Flow in Organized Mammalian CNS Tissue Cultures. J. Neurobiology (expected publication date January, 1976).